Various spiral oven systems are known.
For example, U.S. Pat. No. 5,850,781 describes a multi-heating zone, single spiral oven. A spiral conveyor helically winds around a rotating drum. Heating is provided in zones within the oven. The zones are arranged vertically, i.e., an upper zone and a lower zone. Each zone has at least one ventilation device and heating device for circulating hot air through the zone. Each zone preferably has two ventilators, each with a heating device, which cover approximately half of each spiral conveyor winding.
U.S. Pat. Nos. 7,107,899 and 5,329,916 describe dual spiral ovens. In these patents two rotating drums within the oven are helically surrounded by conveyors wherein the output of one spiral conveyor communicates products onto the input of the next spiral conveyor. Heating elements in U.S. Pat. No. 7,107,899 are arranged as helical electrical coils or hollow tubes that underlie the spiral conveyor. The heating elements in U.S. Pat. No. 5,329,916 are arranged in overhead air ducts.
The present inventor has recognized that it would be desirable to provide a compact spiral oven that provides an optimized and efficient cooking.